Bhatt Tanvi, Wang Yiru, Wang Shuaijie, Kannan Lakshmi
Department of Physical Therapy, College of Applied Health and Sciences, University of Illinois at Chicago, Chicago, IL, United States.
Front Sports Act Living. 2021 Aug 16;3:697169. doi: 10.3389/fspor.2021.697169. eCollection 2021.
This study examined the effects of perturbation training on the contextual interference and generalization of encountering a novel opposing perturbation. One hundred and sixty-nine community-dwelling healthy older adults (69.6 ± 6.4 years) were randomly assigned to one of the three groups: slip-perturbation training (St, = 67) group received 24 slips, trip-perturbation training (Tt, = 67) group received 24 trips, and control (Ctrl: = 31) group received only non-perturbed walking trials (ClinicalTrials.gov NCT03199729; https://clinicaltrials.gov/ct2/show/NCT03199729). After training, all groups had 30 min of rest and three post-training non-perturbed walking trials, followed by a reslip and a novel trip trial for St, a retrip and a novel slip trial for Tt, and randomized novel slip and trip trials for Ctrl. The margin of stability (MOS), step length, and toe clearance of post-training walking trials were compared among three groups to examine interferences in proactive adjustment. Falls, MOS at the instant of recovery foot touchdown, and hip height of post-training perturbation trials were investigated to detect interferences and generalization in reactive responses. Results indicated that prior adaptation to slip perturbation training, resulting in walking with a greater MOS (more anterior) and a shorter step length ( < 0.01) than that of the Ctrl group, would be associated with a greater likelihood to forward balance loss if encountered with a trip. The trip adaptation training mainly induced a higher toe clearance during walking ( < 0.01) than the Ctrl group, which could lead to reduced effectiveness of the reactive response when encountered with a novel slip. However, there was no difference in the reactive MOS, limb support, and falls between the control group and the slip and trip training groups on their respective opposing novel perturbation post-training (MOS, limb support, and falls for novel slip: Tt = Ctrl; for the novel trip: St = Ctrl, both > 0.05). Current findings suggested that, although perturbation training results in proactive adjustments that could worsen the reactive response (interference) when exposed to an unexpected opposing perturbation, older adults demonstrated the ability to immediately generalize the training-induced adaptive reactive control to maintain MOS, to preserve limb support control, and to reduce fall risk.
本研究考察了扰动训练对遭遇新型反向扰动时的情境干扰和泛化能力的影响。169名社区居住的健康老年人（69.6±6.4岁）被随机分为三组之一：滑倒扰动训练（St，n = 67）组接受24次滑倒训练，绊倒扰动训练（Tt，n = 67）组接受24次绊倒训练，对照组（Ctrl：n = 31）仅进行无扰动步行试验（ClinicalTrials.gov NCT03199729；https://clinicaltrials.gov/ct2/show/NCT03199729）。训练后，所有组休息30分钟，进行三次训练后无扰动步行试验，随后St组进行一次重新滑倒和一次新型绊倒试验，Tt组进行一次重新绊倒和一次新型滑倒试验，Ctrl组进行随机的新型滑倒和绊倒试验。比较三组训练后步行试验的稳定裕度（MOS）、步长和脚趾间隙，以检查主动调整中的干扰情况。研究训练后扰动试验中的跌倒情况、恢复脚着地瞬间的MOS以及髋部高度，以检测反应性反应中的干扰和泛化能力。结果表明，与对照组相比，先前适应滑倒扰动训练会导致步行时具有更大的MOS（更靠前）和更短的步长（P<0.01）；如果遭遇绊倒，向前平衡丧失的可能性更大则。绊倒适应训练主要导致步行时脚趾间隙高于对照组（P<0.01），这可能会导致在遭遇新型滑倒时反应性反应的有效性降低。然而，在各自反向新型扰动训练后，对照组与滑倒和绊倒训练组在反应性MOS、肢体支撑和跌倒方面没有差异（新型滑倒时的MOS、肢体支撑和跌倒：Tt = Ctrl；新型绊倒时：St = Ctrl，均P>0.05）当前研究结果表明，尽管扰动训练会导致主动调整，在遭遇意外反向扰动时可能会使反应性反应（干扰）恶化，但老年人表现出能够立即将训练诱导的适应性反应控制进行泛化以维持MOS、保持肢体支撑控制并降低跌倒风险的能力。
